Ritalin,
If you have to tug at your shorts or if they are slipping forward than they are not good shorts. 8 panel is good but it sounds like the wrong pair of shorts for you.
Try some online stores and get some Castelli, Pearl Izumi or Voler shorts. Not the cheap ones but look in the $80-$130 range retail. They are usually on sale so you can probably get them for $50-$90.
If you haven't tried bib shorts, I will highly recommend them as well. They are the most comfortable.
I will highly recommend the Castelli bib shorts with progetto Y chamois.
Believe me, they will seem cheap once you try them. Total comfort and they will last longer than the cheap shorts.